Hydrochlorothiazide is an antihypertensive drug with diuretic effect, which is mainly used to lower blood pressure by improving sodium and water retention in the body through diuresis. For the application of primary hypertension, especially for the elderly or hypertensive patients with heart failure, like Cushing’s syndrome in secondary hypertension, hydrochlorothiazide can also be applied to improve the body’s sodium and water retention. However, there are some side effects when applying hydrochlorothiazide in hypertension, such as the diuretic effect of hydrochlorothiazide, which may lead to lower potassium level in the body and easily lead to electrolyte disturbance. Hydrochlorothiazide may affect the metabolism of uric acid and blood sugar in the body, so it should not be used for people with elevated blood sugar or elevated uric acid.